Electric storage devices such as electric double-layer capacitors are widely being used as small, lightweight batteries capable of achieving comparatively high capacities.
Such electric storage devices are manufactured by first forming an electrode by applying a polarizing electrode layer to both surfaces of a collector electrode configured of aluminum foil and then layering the electrodes with separators therebetween, as disclosed in Patent Document 1, for example.    Patent Document 1: Japanese Unexamined Patent Application Publication No. 2010-123988